NZeem® is an empirical model that predicts mean annual sediment yield from a given catchment, based on annual rainfall, type of terrain and percentage of woody vegetation cover.
NZeem® partitions the New Zealand landscape according to the factors controlling erosion: rock type, land form (especially slope angle), rainfall and land cover. The erosion co‑efficient (a) is a measure of inherent erosion susceptibility related to land-form characteristics (geology, slope angle, etc). The rock type and land-form data comes from the NZ Land Resource Inventory.
The model is calibrated on about 200 sediment yield data sets from most regions in New Zealand. NZeem® is claimed to be applicable to all types and sizes of catchments (Dymond et al, 2010). It also builds on earlier work resulting in a database and digital map of mean specific sediment yield (kg / km2 / yr) produced by NIWA and Landcare Research as part of a project funded by the Foundation for Research Science and Technology for studying carbon transfers associated with erosion (Hicks et al, 2003).
|State of Development||Released and updated|
|Management Domains||Land, Natural Hazards|
|Intended End Users||Researchers, local and regional councils|
|Spatial Extents||Local (i.e. Catchment or District), Regional, National|
|Steady State or Dynamic||Dynamic|
|Level of Integration||Environmental|
|Key Input Data||Land Use, Land Cover, Rainfall Geology and soil types|
|Input Data Formats||Raster GIS|
|Key Output Data||Erosion rate|
|Output Data Formats||Raster GIS|
|Open/Closed Source||Closed Source|
|Licence Type||Data licence required|
|Licence Purchase Contact||
+64 6 353 4800 Landcare Research
Private Bag 11052
Manawatu Mail Centre
Palmerston North 4442,
|Operating Systems||MS Windows, Mac OS X, Linux, Dos executable|
|Software Needed||Internet Browser|
|User Interface||Please Select Web page|
|Ease of Use||Easy Just clicking in a web browser.|
|Use in Policy Process||Plan (Policy Formulation), Do (Policy Implementation)|
|Support||Contact John Dymond for any questions.|
|Programming Language||Two deployments: (1) Python+RIOS or (2) Imagine Spatial Modeller|
|Methods included for calibration and validation||Measurements of sediment yield in rivers to validate.|
|Methods included for managing uncertainty||Uncertainty has been assesed but is not part of the webpage|
This is in the manual
|Keywords||erosion, sediment, rivers, farm plans, soil conservation
|Linkages to other Models|
Requires input from the Landcare Research's highly erodible land model. http://lris.scinfo.org.nz/layer/178-nzeem-erosion-rates-north-island/ http://lris.scinfo.org.nz/layer/176-nzeem-erosion-rates-south-island/
Dymond JR, Betts HD, Schierlitz CS (2010). An erosion model for evaluating land-use scenarios in New Zealand. Environmental Modelling and Software 25: 289-298
Dymond JR, Shepherd JD 2006. Highly erodible land in the Manawatu-Wanganui Region. Landcare Research Contract Report LC0607/027 to MAF Policy.
Dymond J, Shepherd J and Page M 2008. Roll out of erosion models for Regional Councils. Landcare Research Contract Report LC0708/094
Barry, L. et al. 2011 Valuing Avoided Soil Erosion by Considering Private and Public Net Benefits. Paper at NZARES Conference
The Waikato Regional Council (WRC) Healthy Rivers: Plan for Change/Wai Ora: He Rautaki Whakapaipai aims to reduce inputs of sediment, bacteria and nutrients (primarily nitrogen and phosphorus) to water bodies (including groundwater) in the Waikato and Waipa River catchments.
Soil erosion in New Zealand exports much sediment and particulate organic carbon (POC) to the sea.
Assessing erosion in the Waipa catchment using the New Zealand Empirical Erosion Model (NZeem®), Highly Erodible Land (HEL), and SedNetNZ models - WRC Technical Report TR201354